These two brain systems help humans understand the intentions of simple gestures, interpret the meaning of those gestures and place them into context.

The researchers used a group of volunteers (objects) to talk about emotional events in their lives while being videotaped. Later, these volunteers watched themselves on video and evaluated whether they felt positively or negatively while talking about these live events.

Then, a second group of volunteers (perceivers) watched the same videotapes and were asked to evaluate the positive or negative experience of the initial volunteers as they described their life events while also hooked up to functional MRI scanning devices to measure which brain systems were activated.
When the perceivers were accurate about the emotional experience, the same brain systems, the parietal and premotor cortex were activated.

Interestingly, when the perceivers were wrong, a third brain system was activated that involves the control and management of one’s own feelings.

This suggested to the researchers that a persons attention to their own feelings may cause them to miss the gestures and other behaviors linked to the feelings of others.